Using a Movable RFID Antenna to Automatically Determine the Position and Orientation of Objects on a Tabletop

Augmented tabletop games support players by sensing the context of game figures (i.e., position and/or orientation) and then using this information to display additional game information, or to perform game related calculations. In our work we try to detect the position and orientation of game figures using small, unobtrusive passive RFID tags. In order to localize our multi-tagged objects, we use a small movable antenna mounted underneath the table to scan the game environment. While this approach is not capable of real-time positioning, it achieves a very high accuracy on the order of a few millimeters. This article describes our experimental setup, discusses the trade-off between speed and accuracy, and contrasts our approach with a multi-antenna setup.